1. Field of the Invention
This invention is related to a sight for an archery bow. In particular, -this invention is directed to a sight for an archery bow that maintains the axis of the sight normal to the archer""s sighting eye.
2. Description of Related Art
FIG. 1 shows a perspective view of a conventional bow sight 10. The bow sight 10 is attached to a bow (not shown) by a support bar 12. The support bar 12 supports a frame 14 which retains a lead screw 16. The lead screw 16 is connect to a knurled adjusting knob 18. The lead screw 16 is threadably entrained within an elevation block 20 that may be moved upward or downward, as shown by arrow A, by rotating the knurled knob 18. The elevation block 20 is connected to a sighting device 22 through a windage block 28. Therefore, by turning the adjusting knob 18, the sighting device 22 may be moved upward or downward to adjust the elevation of flight of an arrow from the bow.
The elevation block 20 also includes a transversely extending screw 24 that is attached to a knurled knob 26. The transversely extending screw 24 is threadably entrained by the windage block 28. The windage block 28 is connected to the sighting device 22. An archer may adjust the sighting device 22 by rotating knurled knob 26 and moving the sighting device 22 in the direction of arrow B to adjust for wind.
One of the problems with the conventional bow sight that was discovered by the inventor is that an archer""s line of sight through the sighting device 22 may not be normal to the sighting device 22. FIG. 2 shows an archer 30 using a conventional sighting device 10 to sight a target 32. FIG. 2 shows that the axis xcex1 of the sighting device of the bow sight 10 does not coincide with the line of sight xcex2 of the archer 30 to the target 32. The angle xcex3 between the axis a and the line of sight xcex2 causes error in the sighting of an arrow to the target 32. In the example shown in FIG. 2, the archer""s line of sight xcex2 falls on the target 32 at a point that is lower than the point on the target 32 upon which the axis xcex1 of the sighting device of the bow sight 10 falls. Thus, the archer""s line of sight xcex2 does not provide a correct sight that corresponds to the axis xcex1 of the sighting device of the bow sight 10.
An exemplary sighting device of the bow sight 10 is a lens 34 carrying a filament 36 as shown in FIGS. 1, 3 and 4. FIG. 3 shows an exemplary sight picture of an archer 30 when the axis xcex1 of the sighting device 22 does not coincide with the line of sight xcex2 of the archer 30. With this sight picture a portion of the length of the filament 36 is visible to the archer. Therefore, the filament 36 is not focused and appears to have a height h that is greater than the radius r of the filament 36.
FIG. 4 shows a correct sight picture. In particular, the sight picture shown in FIG. 4 is provided when the line of sight xcex2 of the archer coincides with the axis xcex1 of the sighting device 22. The sight picture of FIG. 4 provides an accurate aim to a target while the sight picture of FIG. 3 does not provide an accurate aim.
An exemplary embodiment of a bow sight in accordance with the present invention provides a frame and an elevation block that cooperate to maintain the approximate coincidence of the axis xcex1 of the sighting device 22 with the line of sight xcex2 of an archer. An exemplary embodiment of the invention maintains this coincidence even when the bow sight is adjusted for elevation. The exemplary embodiment of the bow sight of the present invention has a frame with radiused guide ways through which the elevation block of the sighting device travels when being adjusted for elevation. In other words, even though the elevation and windage of the sighting device may be adjusted, the sighting device is always normal to the line of sight of the archer. The radius of the radiused guide ways approximately corresponds to the distance from the archer""s eye to the sighting device 22 on the bow sight 10.
Another exemplary embodiment of the present invention includes a quick release carrier for the sighting device. The quick release carrier maintains the alignment of the sighting device with the archer""s line of sight. Therefore, the exemplary bow sight of the invention may have the sighting device removed from the bow sight for storage and the bow sight may be reassembled without affecting the alignment of the sighting device with the archer""s line of sight when the sighting device is removed and replaced.
Yet another exemplary embodiment of the bow sight in accordance with the present invention also includes a frame that is of a configuration that may be extruded prior to machining. Conventional bow sight frames are difficult to manufacture. By contrast, the frame of the bow sight in accordance with the present invention may be easily manufactured by extruding and subsequent machining. The frame is also unique in that it completely encloses a void or hollow space.
These and other features and advantages of this invention are described in or are apparent from the following detailed description of the preferred embodiments.